1. Field of the Invention
The present invention relates to a liquid crystal display device which includes a liquid crystal layer between a pair of substrates.
2. Description of the Related Art
With a liquid crystal display device using liquid crystal, light from light sources passes through a liquid crystal layer, a color filter, a polarizing plate, etc. before an image is recognized. In this case, a polarizing plate is provided at the outermost surface of a liquid crystal display device for a personal computer monitor or a liquid crystal television. To restrain surface reflection, an anti-glare (AG) film having fine irregularities or an antireflection film is provided on the surface of the polarizing plate. There is a liquid crystal panel made of a glass plate having a thickness of about 0.5 to 0.7 mm under the polarizing plate.
The glass plate under the polarizing plate for such a personal computer monitor and a liquid crystal television has a thickness of 0.5 to 0.7 mm depending on products. Therefore, the glass plate may be broken if tableware, a flower vase, a toy, or the like collides with it with large impact. There is a trend toward increasing the screen size of both a personal computer monitor and a liquid crystal television. The larger the screen size with a fixed glass plate thickness, the smaller becomes the resistance to shock and therefore the glass plate is susceptible to breakage even with very small impact. Accordingly, it is contemplated to improve the resistance to shock by providing a transparent substrate (hereafter referred to as protection plate) at the outermost surface as is the case with a cellular phone.
However, since there is a gap between the glass plate and the polarizing plate, a severe reflection of surrounding scenery to the image display plane takes place on three surfaces: both surfaces of the protection plate and the surface of the polarizing plate. This arises a problem of degraded visibility in a well-lighted area.
JP-A-11-174417 discloses a technique in which the gap between the protection plate and the polarizing plate is filled with a transparent organic medium and thereby reflection on the polarizing plate and on the polarizing plate side of the protection plate is restrained.
However, when this transparent organic medium is formed, the problem is that air bubbles enter between the protection plate and the liquid crystal panel. For example, if the protection plate is larger than the liquid crystal panel, the end frame which is a non-pixel region of the liquid crystal panel and air bubbles at the end will be watched disadvantageously.
Therefore, it is contemplated to form a black-painted portion at ends of four sides on the protection plate to hide the frame and air bubbles. The same measure is performed also for the glass plate used for a front filter of the PDP. When this measure (black painting) is performed with an inorganic material, it is normally referred to as black ceramic (refer to JP-A-2000-340985). However, since it is necessary to perform hardening at high temperature, in many cases, a black-painted portion is formed using a paint in which black coloring matters are distributed and dissolved. The glass plate of the front filter of the PDP is preliminarily subjected to black painting. Therefore, even if the surface is wiped a number of times to remove dust and dust thereon, the black-painted portion will not exfoliate. Further, the front surface is formed under the glass plate having a higher flatness and the black-painted portion also has a higher flatness in the visible surface direction. The surface of the pixel region is also a glass plate having a higher flatness, providing a sense of integration of the black-painted portion and the pixel region as well as excellent design features.